Warning: contains spoilers.
With the help of the pause button and a pot of strong coffee, we’ve picked through Sherlock’s series four finale The Final Problem to seek out the nerdy references and painstakingly added background details. (You can find the same for the previous episodes here and here.)
1. Starting with the obvious, The Final Problem is of course the title of Sir Arthur Conan Doyle’s 1893 short story in which Sherlock Holmes and Professor Moriarty appear to tumble to their deaths in the Reichenbach Falls. Andrew Scott’s Moriarty references the title several times in series two finale The Reichenbach Fall.
2. The very first shot of The Final Problem is a blue eye opening, just like the very first shot of The Abominable Bride.
3. Eurus’ brain is so powerful that it went to the trouble of branding her Mind Palace plane with this three-pronged t-shaped logo. Is it significant in any way?
4. The plane of unconscious passengers is an image used in series two opener A Scandal In Belgravia, in which the British Government stuffed an unmanned plane due to be attacked by terrorists with corpses so they could continue their surveillance of the cell undetected and avoid casualties.
5. Nobody will have missed that this Tudor-style painting hanging in Mycroft’s opulent home is of Mycroft himself. Excellent work there by the production design team and artists. If I were Mark Gatiss, that little beauty would have been in the boot of my car the minute that scene was in the can.
6. Mycroft’s attachment to his family is made clear in the episode, not only when he smiles at the home video of little Sherlock hugging him, but also by this framed photograph of their parents he keeps on his sideboard.
7. Sherlock costumed his ‘little horror girl’ in a blue dress with her hair in bunches. Yes, there’s a hint of The Shining twins and Esther from Orphan in the look but it also happens to be exactly how Eurus is dressed in the beach flashbacks: blue dress, hair in bunches. Lucky guess or bubbling up childhood trauma?
8. Mark Gatiss has made no secret over the years of his plan for Mycroft’s elegant umbrella to contain a John Steed-style sword, and in The Final Problem, it finally arrives. In this web chat over on the terrific Sherlockology, Gatiss says this about Mycroft’s iconic accessory: “It originally came from wanting to create a good silhouette in the first scene in ‘Pink’ where Mycroft and John meet. I wasn’t trying to invoke John Steed but there’s something very Establishment about it- and that’s what Mycroft is. The Dark Government and the Old School Tie. I think it’s his comfort blanket. He may even sleep with it. The umbrella comes from a wonderful old shop in New Oxford St. They still advertise ‘dagger canes’ and ‘sword sticks’ but, to their great regret, are no longer allowed to stock them!
9. Musgrave Hall, the Holmes family ancestral seat, is named for 1893 Conan Doyle story The Adventure Of The Musgrave Ritual. (Mycroft later describes Eurus’ torturing Sherlock with her coded song as “her little ritual”.) In the original story, a verse riddle is handed down from generation to generation and not solved until Sherlock Holmes follows its instructions to discover concealed treasure dating back to the time of the English Civil War.
10. When describing there always being “honey for tea” at Musgrave Hall, Mycroft appears to paraphrase 1912 Rupert Brooke poem The Old Vicarage, Grantchester (“And is there honey still for tea?”) the song of an exile nostalgic for the England of the past.
11. Tell me I’m mad but doesn’t the headstone behind young Sherlock read “Brenda Spencer”, as in real-life “I don’t like Mondays” 1970s school shooting mass murderer Brenda Spencer? It could be a deliberately macabre reference to dangerous young girls, or… I need a new contact lens prescription. Probably the latter.
12. Mrs Hudson’s vacuuming music of choice? Iron Maiden’s The Number Of The Beast. As detailed here, the plane Sherlock was flown off to his four-minute exile on at the end of His Last Vow was on loan to the production company from Iron Maiden lead singer Bruce Dickinson. So now you know.
13. The Master’s island prison in Doctor Who’s The Sea Devils may have been part inspiration for the location of Sherrinford, but its décor seems to pay homage to the work of Bond set designer Ken Adam on the likes of Dr No and Moonraker. (Eurus’ video message games, as has been widely cited online, appear to have a touch of Saw about them.)
14. Vince the sailor on the boat Sherlock, John and Mycroft commandeered after a helicopter air drop, was played by Ralph Ineson, who played deplorable travelling salesman Chris Finch on Martin Freeman’s old show, The Office.
15. The Bach piece Eurus stops Sherlock from playing because “[he] clearly [doesn’t] understand it” is his Chaconne for Solo Violin, as identified by Kevin Wright on Twitter. When instructed to “play you” he plays The Woman / Irene’s Theme, first heard in A Scandal In Belgravia.
16. Sherlock’s Production Designer extraordinaire, Arwel Wyn Jones, has a thing about elephants. Look back over all four series and they pop up in print and ornament form all over the place. Where is the elephant in The Final Problem’s room? Check out the make of the missing glass in Eurus’ cell.
17. Fans won’t have missed John using his and Sherlock’s code phrase ‘Vatican Cameos’ to warn him over their comms devices that Sherrinford’s governor has been compromised. Originally, it refers to a line in Doyle’s The Hound Of The Baskervilles in which Holmes references being “exceedingly preoccupied by that little affair of the Vatican cameos” during a case for the Pope. It was first used in the TV show in A Scandal In Belgravia, then again in The Sign Of Three.
18. The orderlies at Sherrinford wear yellow medical scrubs with a custom lapel crest featuring some kind of fortress. As pyjamas, these would make excellent official BBC merchandise.
19. Either Moriarty or Eurus is a bit of a geek. When his pre-recorded “red alert” message plays when the Governor locks down Sherrinford he says “Klingons attacking lower decks! Also cowboys in black hats! Darth Vader!”
20. Unlike Scaramanga in Ian Fleming’s The Man With The Golden Gun (whose private island may also have been one of the inspirations for the location of Sherrinford), Moriarty is able to whistle. When he does so at the prison, he’s answered by a choir of criminals. Fleming’s novel repeated the very odd, very stupid theory that “a man who cannot whistle has homosexual tendencies…” a note read by M in Scaramanga’s file.
21. In Doyle novel The Valley Of Fear we’re told that Professor Moriarty’s brother is “a station master in the west of England”. In The Final Problem Eurus tells Sherlock that Moriarty was happy to record several messages for her because he was jealous of his brother the station master. TV stations for train stations is a perfect BBC Sherlock modern swap.
22. The sibling murder Eurus has Sherlock solve as the second level of her experiment refers to Doyle’s The Adventure Of The Three Garridebs. Nathan, Alex and Howard Garrideb weren’t brothers in the original story (in fact, one of them wasn’t even real). In the Doyle tale, Dr Watson is shot in the leg, which enrages Sherlock Holmes, a reaction that delights Dr Watson who writes “It was worth a wound, it was worth many wounds, to know the depth of loyalty and love which lay behind that cold mask.”
23. Leave a message on forensic pathologist Molly Hooper’s phone and you’ll hear her punning voicemail greeting: “Hi, this is Molly at the dead centre of town”. Geddit?
24. Think back to The Six Thatchers and the repeated motif of water reflecting on Sherlock’s face. The same happens here as he realises what Eurus did to little Victor Trevor, his only childhood friend, connecting the two episodes.
25. Victor Trevor was the name of Holmes’ university friend who featured in the earliest chronological Sherlock Holmes case from Doyle, The Adventure Of The Gloria Scott.
26. Lestrade telling his young colleague that Sherlock Holmes is a good man calls back to A Study In Pink when he said “Sherlock Holmes is a great man and I think one day, if we’re very, very lucky, he might even be a good one”. Achievement unlocked.
27. It’s not easy to miss but worth pointing out that the toy Eurus is playing with in all the beach flashbacks is a little plane, a hint towards the truth of the girl on the plane.
28. Speaking of whom, the young actor who plays said girl on plane is Honor Kneafsey and this isn’t her first appearance on Sherlock. She and her older sister played the two girls in A Scandal In Belgravia who weren’t allowed to see their granddad after he died and whom Sherlock traumatised by saying “People don’t really go to heaven when they die. They’re taken to a special room and burned.”
29. Sherlock is evidently a crime fiction fan. One of the charred books on the floor of 221B Baker Street post-explosion is Katherine Neville’s global detective mystery The Eight.
30. Instead of “Miss Me?”, Mary’s second video is entitled “Miss You”.
31. Mary’s video takes us all the way back to the Sherlock pilot A Study In Pink by reshowing the first appearances of Sherlock and John, the former unzipping a body bag at the morgue, the second waking from a PTSD-related nightmare.
32. Despite Mycroft’s warning, the Holmes parents (played of course by Benedict Cumberbatch’s real parents Timothy Carlton and Wanda Ventham) do go to Sherrinford to visit Eurus. And Mother Holmes appears to have forgiven Mycroft his lie by the looks of her comforting hand here.
33. A good friend of Martin Freeman, musician Paul Weller, plays the Viking lying on the floor of 221B Baker Street. Fun fact: according to this photograph, Arthur Conan Doyle once dressed as a Viking for a fancy dress ball.
34. The symbols on the chalk board in the episode’s final moments are a reference to The Adventure Of The Dancing Men, a 1903 Conan Doyle story in which a cypher is used to send messages. The 15 characters on the board are the same as those in the story’s first message and read ‘Am here Abe Slaney’.
35. “People text. Even I text. Her, I mean. The Woman. Bad idea. Try not to, but, you know, sometimes…” said Sherlock to Watson in The Lying Detective. Well, the detective wasn’t lying about that by the looks of the message that appears on screen in episode three’s final moments. “You know where to find me. SH” It has to be to her, doesn’t it?
36. One of the white overall-wearing decorators helping to reconstruct 221B Baker Street in the episode’s final moments may just be Sherlock set designer Arwel Wyn Jones. It’s only proper that he be part of putting his most famous creation back together.
37. The final shot of the episode, and perhaps even the whole show, is Sherlock and John running Batman-and-Robin-style out of Rathbone Place, an homage to legendary Sherlock Holmes actor Basil Rathbone.
38. I’ve never spotted these (are they US-only?), but according to Twitter user Kristina, red letters in the closing credits of the episode spell out the word ANEMOI, the collective name of the Greek wind Gods, including, of course, Eurus.